The appeal comes after four of the country's five legal political parties adopted the military leader, General Sani Abacha, as their presidential candidate, with the fifth considering following suit.

Opposition groups who form the United Action for Democracy, UAD, accused the government of manipulating the political process so that the General remains in power.

Chima Ubani of the UAD said that General Abacha's attempt to become a civilian president is against the wishes of the people.

The BBC's Lagos correspondent says mass opposition action poses a problem for the government, which maintains that the five parties represent the views of all Nigeria.

The military leader's civilian clothes

The government argues that if the general takes off his military uniform to become a civilian president, he will have kept his promise to hand over to civilian rule - a transition to what the government calls Nigerian-style democracy.

But if General Abacha becomes the joint candidate for most of the political parties, he may be unopposed in August's presidential elections, paving the way for him to stay on in power indefinitely.

The country's largest political grouping, the United Nigeria Congress Party, has endorsed General Abacha, and was joined by three other parties on Saturday - the National Centre Party of Nigeria, the Congress for National Consensus and the Democratic Party of Nigeria.

All five of Nigeria's legal political parties are government-funded and none represent any of General Abacha's real opponents.

The only party which may still adopt a presidential candidate other than General Abacha, is meeting on Sunday to make its choice.

The party, the Grass Roots Democratic Movement, is considering several candidates, including a former police chief, and General Abacha.

The general came to power in 1993 after a political crisis following the annulment of elections.